A women, wearing a niqab despite a nationwide ban on the Islamic face veil in France in 2011Reuters/Charles Platiau

A young Muslim couple has been forbidden from marrying in the French city of Nice after their civil wedding celebration was suspended by court order because of "radicalisation" fears.

On 23 March, the young woman, 21, and her 28-year old fiance went to the Town Hall registry office dressed in an outfit "similar to the niqab" to express their discontent after their ceremony was cancelled on 21 March.

"I have decided to oppose this marriage with the prosecutor as provided in Article 175-2 of the Civil Code, since I had a legitimate doubt about the sincerity of the union," Christian Estrosi, the city mayor from the centre-right UMP party, said on 24 March in a statement.

The city's unit fighting against extremist fundamentalism had signalled the "bride was engaged in amplified radicalisation in recent months", Estrosi said.

The surveillance unit, which helps 20 families, has already received 200 calls and 30 reporting of radicalised conduct since it was set up in October 2014, amid concerns over the growing numbers of youths joining the jihad.

"When you also know that the future husband was sentenced, less than two months ago, for group violence against a baker who had committed the only crime of selling ham sandwiches and Baba au Rhum (a rum-soaked cake), I consider it was legitimate for me to seize the prosecutor, which launched an investigation," Estrosi explained.

The man was also monitored by the General Directorate for Internal Security (Direction Générale de la Sécurité Intérieure, DGSI), the French intelligence agency, because it was believed he was likely to wage jihad abroad. The groom's lawyer declined to comment, saying he wished to speak with his clients.

In April 2014, French Interior Minister Bernard Cazeneuve submitted an anti-radicalisation plan aimed at French citizens or residents believed to be at risk of involvement in violent extremism - such as joining jihadist groups in Syria.